Actually, Don, in all his infinite wisdom, actually has a safety device for that exact scenario on the old TM's
If you read the instructions it says to consistently use the same type of battery with your TM. If you have a 9.6v 1500mah pack, ONLY USE 9.6v 1500mah packs. Don't be switching between an 8.4v large and 9.6v mini, etc.
Now obviously the triggermasters have memory since they remember settings, well they also remember the highest recorded input voltage!
This means, you plug in a fully charged 11.1v LiPo, it records the input voltage at 12.6v. You game with the LiPo for a few hours and drain the cells down to 10.8v. You don't charge your LiPo and come back next week, you plug in your batt at 10.8v, but because the TM remembers the 12.6v input voltage, your cutoff is still 10v
By experience I learned this by switching from 9.6v NiMH immediately to a 7.4v LiPo. I plugged in the LiPo, tried to shoot and it just gave me the battery low warning and refused to function. 80% of the peak voltage of a 9.6v NiMH is around 8.4v.
IMO the old TM MKIII is the safest SW-comp to be used with LiPo's if you don't have a PCB. Internal fuse, MOSFET, input voltage memory, and 80% cutoff that's safely above the minimum voltage of LiPo's